I'm currently preparing for a music video. A couple of scenes will need a misty dreamlike look to it (example down below)? I understand old glass is the best to get this look, but I would like to know the different type that I could rent.

I currently live in the UK wanted to know the most accessible filter and lenses needed to provide an image like this?

Tiffin makes a plugin suite called DFX that can replicate nearly all the tiffin filters in post. I use it a lot for stylistic filters like diffusion, promist, etc.Of course, while I think it has ND filter and polarizer options, you need to use real ND's and polar filters on set.